Active smoking and survival following breast cancer among African American and non-African American women in the Carolina Breast Cancer Study.
ABSTRACT: To examine racial differences in smoking rates at the time of breast cancer diagnosis and subsequent survival among African American and non-African American women in the Carolina Breast Cancer Study (Phases I/II), a large population-based North Carolina study.We interviewed 788 African American and 1,020 Caucasian/non-African American women diagnosed with invasive breast cancer from 1993 to 2000, to assess smoking history. After a median follow-up of 13.56 years, we identified 717 deaths using the National Death Index; 427 were breast cancer-related. We used Cox regression to examine associations between self-reported measures of smoking and breast cancer-specific survival within 5 years and up to 18 years after diagnosis conditional on 5-year survival. We examined race and estrogen receptor status as potential modifiers.Current (vs never) smoking was not associated with 5-year survival; however, risk of 13 year conditional breast cancer-specific mortality was elevated among women who were current smokers at diagnosis (HR 1.54, 95% CI 1.06-2.25), compared to never smokers. Although smoking rates were similar among African American (22.0%) and non-African American (22.1%) women, risk of breast cancer-specific mortality was elevated among African American (HR 1.69, 95% CI 1.00-2.85), but only weakly elevated among non-African American (HR 1.22, 95% CI 0.70-2.14) current (vs. never) smokers (P Interaction = 0.30). Risk of breast cancer-specific mortality was also elevated among current (vs never) smokers diagnosed with ER- (HR 2.58, 95% CI 1.35-4.93), but not ER+ (HR 1.11, 95% CI 0.69-1.78) tumors (P Interaction = 0.17).Smoking may negatively impact long-term survival following breast cancer. Racial differences in long-term survival, as related to smoking, may be driven by ER status, rather than by differences in smoking patterns.
Project description:Background:The purpose of this study was to examine whether at-diagnosis smoking and postdiagnosis changes in smoking within five years after breast cancer were associated with long-term all-cause and breast cancer-specific mortality. Methods:A population-based cohort of 1508 women diagnosed with first primary in situ or invasive breast cancer in 1996 to 1997 were interviewed shortly after diagnosis and again approximately five years later to assess smoking history. Participants were followed for vital status through December 31, 2014. After 18+ years of follow-up, 597 deaths were identified, 237 of which were breast cancer related. Multivariable Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results:Compared with never smokers, risk of all-cause mortality was elevated among the 19% of at-diagnosis smokers (HR=1.69, 95% CI=1.36 to 2.11), those who smoked 20 or more cigarettes per day (HR=1.85, 95% CI=1.42 to 2.40), women who had smoked for 30 or more years (HR=1.62, 95% CI=1.28 to 2.05), and women who had smoked 30 or more pack-years (HR=1.82, 95% CI=1.39 to 2.37). Risk of all-cause mortality was further increased among the 8% of women who were at-/post-diagnosis smokers (HR=2.30, 95% CI=1.56 to 3.39) but was attenuated among the 11% women who quit smoking after diagnosis (HR=1.83, 95% CI=1.32 to 2.52). Compared with never smokers, breast cancer-specific mortality risk was elevated 60% (HR=1.60, 95% CI=0.79 to 3.23) among at-/postdiagnosis current smokers, but the confidence interval included the null value and elevated 175% (HR=2.75, 95% CI=1.26 to 5.99) when we considered postdiagnosis cumulative pack-years. Conclusions: Smoking negatively impacts long-term survival after breast cancer. Postdiagnosis cessation of smoking may reduce the risk of all-cause mortality. Breast cancer survivors may benefit from aggressive smoking cessation programs starting as early as the time of diagnosis.
Project description:This study assesses the contribution of smoking to all-cause mortality among a primarily minority cohort of urban transit operators. Survey and medical exam data, obtained from 1,785 workers (61% African American; 9% female) who participated in the 1983-1985 San Francisco MUNI Health and Safety Study, were matched against state and national death records through 2000. At baseline, approximately 45% of the workers were current smokers, 30% were former smokers, and 25% had never smoked. Covariates were demographic factors (gender, age, race/ethnicity) and alcohol use (average number of drinks per week). There were 198 deaths during the follow-up period. Kaplan-Meier survival analysis indicated that the probability of survival did not differ between former and current smokers, but was significantly lower compared to never smokers (p < 0.001). Data were further analyzed using Cox regression with age, gender, race/ethnicity, years of smoking, and average weekly number of drinks as predictors of mortality. The results showed that years of smoking significantly contributed to mortality (hazard ratio [HR] = 1.023; p < 0.001). Compared to Asian-American transit operators, elevated mortality risk was observed for African-American operators (HR = 2.78, p < 0.01) and white operators (HR = 2.93, p < 0.01). Gender and average weekly number of drinks were not significantly associated with mortality. Although rates of smoking have declined over the past two decades among blue-collar workers, elevated prevalence of former smoking will likely contribute to excess mortality among blue-collar populations.
Project description:INTRODUCTION: In women with breast cancer who smoke, it is unclear whether smoking could impair their survival from the disease. METHODS: We examined the relation of smoking at diagnosis to breast cancer-specific and overall survival among 5,892 women with invasive breast cancer treated in one Canadian center (1987 to 2008). Women were classified as never, former or current smokers. Current smokers were further classified according to total, intensity and duration of smoking. Deaths were identified through linkage to population mortality data. Cox proportional-hazards multivariate models were used. A systematic review with meta-analysis combines new findings with published results. RESULTS: Compared with never smokers, current smokers at diagnosis had a slightly, but not statistically significant, higher breast cancer-specific mortality (hazard ratio?=?1.15, 95% confidence interval (CI): 0.97 to 1.37). Among current smokers, breast cancer-specific mortality increased with total exposure to, intensity and duration of smoking (all Ptrend <0.05). Compared to never smokers, breast cancer-specific mortality was 32 to 56% higher among heavy smokers (more than 30 pack years of smoking, more than 20 cigarettes per day or more than 30 years of smoking). Smoking at diagnosis was associated with an increased all-cause mortality rate. A meta-analysis of all studies showed a statistically significant, 33% increased mortality from breast cancer in women with breast cancer who are smokers at diagnosis compared to never smokers (hazard ratio?=?1.33, 95% CI: 1.12 to 1.58). CONCLUSIONS: Available evidence to date indicates that smoking at diagnosis is associated with a reduction of both overall and breast cancer-specific survival. Studies of the effect of smoking cessation after diagnosis on breast cancer-specific outcomes are needed.
Project description:Tobacco smoking is a risk factor in several cancers, yet its roles as a putative etiologic exposure or poor prognostic factor in breast cancer are less clear. Altered DNA methylation contributes to breast cancer development and may provide a mechanistic link between smoking and gene expression changes leading to cancer development or progression.Using a cancer-focused array, we examined methylation at 933 CpGs in 517 invasive breast tumors in the Carolina Breast Cancer Study to determine whether methylation patterns differ by exposure to tobacco smoke. Multivariable generalized linear regression models were used to compare tumor methylation profiles between smokers and never smokers, overall, or stratified on hormone receptor (HR) status.Modest differences in CpG methylation were detected at p < 0.05 in breast tumors from current or ever smokers compared with never smokers. In stratified analyses, HR- tumors from smokers exhibited primarily hypomethylation compared with tumors from never smokers; hypomethylation was similarly detected within the more homogeneous basal-like subtype. Most current smoking-associated CpG loci exhibited methylation levels in former smokers that were intermediate between those in current and never smokers and exhibited progressive changes in methylation with increasing duration of smoking. Among former smokers, restoration of methylation toward baseline (never smoking) levels was observed with increasing time since quitting. Moreover, smoking-related hypermethylation was stronger in HR+ breast tumors from blacks than in whites.Our results suggest that breast tumor methylation patterns differ with tobacco smoke exposure; however, additional studies are needed to confirm these findings.
Project description:INTRODUCTION:The purpose of this study was to explore the association of smoking status and clinically relevant duration of smoking cessation with long-term survival after lung cancer (LC) or colorectal cancer (CRC) diagnosis. We compared survival of patients with LC and CRC who were never-smokers, long-term, medium-term, and short-term quitters, and current smokers around diagnosis. METHODS:We studied 5575 patients in Cancer Care Outcomes Research and Surveillance (CanCORS), a national, prospective observational cohort study, who provided smoking status information approximately 5 months after LC or CRC diagnosis. Smoking status was categorized as: never-smoker, quit >5 years prior to diagnosis, quit between 1-5 years prior to diagnosis, quit less than 1 year before diagnosis, and current smoker. We examined the relationship between smoking status around diagnosis with mortality using Cox regression models. RESULTS:Among participants with LC, never-smokers had lower mortality risk compared with current smokers (HR 0.71, 95% CI 0.57 to 0.89). Among participants with CRC, never-smokers had a lower mortality risk as compared to current smokers (HR 0.79, 95% CI 0.64 to 0.99). CONCLUSIONS:Among both LC and CRC patients, current smokers at diagnosis have higher mortality than never-smokers. This effect should be further studied in the context of tumor biology. However, smoking cessation around the time of diagnosis did not affect survival in this sample. IMPLICATIONS:The results from our analysis of patients in the CanCORS consortium, a large, geographically diverse cohort, show that both LC and CRC patients who were actively smoking at diagnosis have worse survival as compared to never-smokers. While current smoking is detrimental to survival, cessation upon diagnosis may not mitigate this risk.
Project description:The impact of modifiable environmental factors on kidney cancer specific outcomes is under studied. We evaluated the impact of smoking exposure on cancer specific survival in patients with clear cell renal cell carcinoma treated with surgery.From a prospectively maintained database at a single center we collected the characteristics of 1,625 patients with clear cell renal cell carcinoma treated with surgery between 1995 through 2012. We determined the associations of smoking status with advanced disease, defined as AJCC (American Joint Committee on Cancer) stage greater than 2, and with cancer specific survival.The prevalence rate of current, former and never smoking at diagnosis was 16%, 30% and 54%, respectively. Of the patients 62% reported a smoking history of 20 pack-years or greater. Median followup in survivors was 4.5 years (IQR 2.2-7.9). On univariable analysis a smoking history of 20 pack-years or greater was associated with a significantly increased risk of advanced disease (OR 1.43, 95% CI 1.02-2.00). However, it did not achieve an independent association after adjusting for age and gender. Pathological stage and Fuhrman grade adversely affected cancer specific survival on multivariable competing risks analysis. Although the association between smoking and cancer specific survival did not achieve statistical significance on multivariable analysis, the direction of the central estimate (HR 1.5, 95% CI 0.89-2.52) suggested that smoking adversely impacts cancer specific survival. Current smokers faced a higher risk of death from another cause than never smokers (HR 1.93, 95% CI 1.29-2.88).Smoking exposure substantially increases the risk of death from another cause and adversely impacts cancer specific survival in patients with clear cell renal cell carcinoma. Treatment plans to promote smoking cessation are recommended for these patients.
Project description:Cigarette smoking has been shown to increase the risk of developing colorectal cancer, particularly smoking early in life. Little is known about the impact of tobacco use on colon cancer recurrence among colon cancer survivors.The authors prospectively collected lifetime smoking history from stage III colon cancer patients enrolled in a phase 3 trial via self-report questionnaires during and 6 months after completion of adjuvant chemotherapy. Smoking status was defined as never, current, or past. Lifetime pack-years were defined as number of lifetime packs of cigarettes. Patients were followed for recurrence or death.Data on smoking history were captured on 1045 patients with stage III colon cancer receiving adjuvant therapy (46% never smokers; 44% past; 10% current). The adjusted hazard ratio (HR) for disease-free survival (DFS) was 0.99 (95% confidence interval [CI], 0.70-1.41), 1.17 (95% CI 0.89-1.55), and 1.22 (95% CI 0.92-1.61) for lifetime pack-years 0-10, 10-20, and 20+, respectively, compared with never smoking (P = .16). In a preplanned exploratory analysis of smoking intensity early in life, the adjusted HR for 12+ pack-years before age 30 years for DFS was 1.37 (95% CI, 1.02-1.84) compared with never smoking (P = .04). The adjusted HR for DFS was 1.18 (95% CI, 0.92-1.50) for past smokers and 1.10 (95% CI, 0.73-1.64) for current smokers, compared with never smokers.Total tobacco usage early in life may be an important, independent prognostic factor of cancer recurrences and mortality in patients with stage III colon cancer.
Project description:BACKGROUND:Chronic inflammation is associated with ovarian carcinogenesis; yet, the impact of inflammatory-related exposures on outcomes has been understudied. OBJECTIVE:Given the poor survival of women diagnosed with ovarian cancer, especially African-Americans, we examined whether diet-associated inflammation, a modifiable source of chronic systemic inflammation measured by the dietary inflammatory index (DII), was associated with all-cause mortality among African-American women with ovarian carcinoma. METHODS:Data were available from 490 ovarian carcinoma patients enrolled in a population-based case-control study of African-American women with ovarian cancer, the African-American Cancer Epidemiology Study. Energy-adjusted DII (E-DII) scores were calculated based on prediagnostic dietary intake of foods alone or foods and supplements, which was self-reported using the 2005 Block Food Frequency Questionnaire. Cox proportional hazards regression was used to estimate risk of mortality overall and for the most common histotype, high-grade serous carcinoma. Additionally, we assessed interaction by age at diagnosis and smoking status. RESULTS:Women included in this study had a median age of 57 y, and the majority of women were obese (58%), had late-stage disease (Stage III or IV, 66%), and had high-grade serous carcinoma (64%). Greater E-DII scores including supplements (indicating greater inflammatory potential) were associated with an increased risk of mortality among women with high-grade serous carcinoma (HR1-unit change: 1.08; 95% CI: 1.01, 1.17). Similar associations were observed for the E-DII excluding supplements, although not statistically significant (HR1-unit change: 1.07; 95% CI: 0.97, 1.17). There was an interaction by smoking status, where the positive association with mortality was present only among ever smokers (HRQuartile 4/Quartile 1: 2.36; 95% CI: 1.21, 4.60) but not among never smokers. CONCLUSIONS:Greater inflammatory potential of prediagnostic diet may adversely impact prognosis among African-American women with high-grade serous carcinoma, and specifically among ever smokers.
Project description:An increasing proportion of US smokers smoke ?10 cigarettes per day (CPD) or do not smoke every day, yet the health effects of low-intensity smoking are poorly understood. We identified lifelong smokers of <1 or 1-10 CPD and evaluated risk of incident cancer among 238,525 cancer-free adults, aged 59-82, in the NIH-AARP Diet and Health Study. A questionnaire administered in 2004-2005 assessed CPD during nine age-periods (<15 to ?70). We estimated hazard ratios (HR) and 95% confidence intervals (CI) using multivariable-adjusted Cox proportional hazards regression with age as the underlying time metric. Of the 18,233 current smokers, (7.6%), 137 and 1,243 reported consistently smoking <1 CPD and 1-10 CPD, respectively. Relative to never smokers, current smokers who reported consistently smoking 1-10 CPD over their lifetime were 2.34 (95% CI?=?1.86-2.93) times more likely to develop smoking-related cancer. Current lifetime smokers of <1 CPD were 1.89 (95% CI?=?0.90-3.96) times more likely to develop tobacco-related cancer, although the association did not reach statistical significance. Associations were observed for lifelong smoking of ?10 CPD with lung cancer (HR?=?9.65, 95% CI?=?6.93-13.43); bladder cancer (HR?=?2.22, 95% CI?=?1.22-4.05); and pancreatic cancer (HR?=?2.03, 95%CI: 1.05-3.95). Among lifelong ?10 CPD smokers, former smokers had lower risks of smoking-related cancer with longer time since cessation and longer smoking duration. Lifelong <1 and 1-10 CPD smokers are at increased risk of incident cancer relative to never smokers and would benefit from cessation, providing further evidence that even low-levels of cigarette smoking cause cancer.
Project description:<h4>Background</h4>The relationship between cigarette smoking and breast cancer risk has been inconsistent, potentially due to modification by other factors or confounding.<h4>Methods</h4>We examined smoking and breast cancer risk in a prospective cohort of 186?150 female AARP (formerly American Association of Retired Persons) members, ages 50-71 years, who joined the study in 1995-96 by responding to a questionnaire. Through 2006, 7481 breast cancers were diagnosed. Multivariable-adjusted hazard ratios (HRs) were estimated, overall and stratified by breast cancer risk factors, using Cox proportional hazards regression. Multiplicative interactions were evaluated using the likelihood ratio test.<h4>Results</h4>Increased breast cancer risk was associated with current (HR 1.19, 95% confidence interval (CI) 1.10-1.28) and former (HR 1.07, CI 1.01-1.13) smoking. The current smoking association was stronger among women without (HR 1.24, CI 1.15-1.35) as compared to those with a family history of breast cancer (HR 0.94, CI 0.78-1.13) (P-interaction=0.03). The current smoking association was also stronger among those with later (? 15 years: HR 1.52, CI 1.20-1.94) as compared with earlier (?12 years: HR 1.14, CI 1.03-1.27; 13-14 years: HR 1.18, CI 1.05-1.32) ages at menarche (P-interaction=0.03).<h4>Conclusions</h4>Risk was elevated in smokers, particularly in those without a family history or late menarche. Research into smoking's effects on the genome and breast development may clarify these relationships.